WASHINGTON — Sen. Mark Kirk, who suffered a major stroke a month ago, is recovering quietly, with careful limits on both his visitors and information about his condition.

Kirk, 52, is being treated at the Rehabilitation Institute of Chicago after undergoing three surgeries at Northwestern Memorial Hospital.

Doctors have said they expect him to regain his mental faculties but have cautioned that he could suffer from lasting paralysis on his left side.

According to doctors, Kirk has asked for his BlackBerry, watched the Super Bowl and started walking on a treadmill. But friends say few people are being allowed to see him.

"No, he's not having a lot of visitors," said Rep. Judy Biggert, a Hinsdale Republican who is a close friend and has been briefed by his aides. She aims to see him, she said, "as soon as they open the doors."

Biggert said she hears he is "moving so much faster than they thought" and is engaged on legislative issues. Even so, she predicted that the "earliest" he will return to Washington is six months after the stroke.

Former Rep. John Porter, a father figure to Kirk, said he'll "rush out" to see him once Kirk's staffers say he is available "to see visitors like me." Kirk was once Porter's chief of staff and held Porter's old House seat for a decade.

Kirk is under the care of Dr. Richard Harvey, medical director of the institute's Center for Stroke Rehabilitation. Harvey is not giving interviews.

Nor are Kirk's aides. Deputy chief of staff Kate Dickens emailed the Tribune: "We have made it clear that there will not be interviews done at this time. To be more clear: There will be no interviews done at this time by the senator, his staff, his family or the hospitals."

Dickens said Kirk's office was "fully operational." Kirk's term runs through January 2017.

In the week after Kirk's first surgery, Northwestern held two news conferences, and reporters were free to ask questions. But since then, officials have handled news on Kirk by issuing statements.

"The family was pretty clear about limiting what they wanted released to the public about the senator's care," Kris Lathan, director of media and public relations at Northwestern Memorial, said this week.

Gloria Wooden, spokeswoman for the rehabilitation institute, said it planned weekly statements on Kirk.

A close friend, Sen. Joe Manchin, D-W. Va., visited Chicago to see Kirk on Jan. 28. "I'm so encouraged with his prognosis and progress," Manchin said in a statement. But Manchin, who spoke to the Tribune before the visit, since has turned down interview requests.

Kirk's medical odyssey began Jan. 21 when he complained of seeing white flecks, numbness in his left arm and unusual sensations in his left leg, according to his internist, Dr. Jay Alexander, who advised Kirk to go to Northwestern Lake Forest Hospital. Kirk did well there initially but "quickly deteriorated," according to a hospital spokesman.

He was transferred to Northwestern Memorial, where he underwent a three-hour surgery in which doctors removed a 4-by-8-inch piece of skull to relieve pressure caused by swelling.

Kirk's was an ischemic stroke, triggered when a vessel that supplies blood to the brain is blocked by a blood clot. That was prompted by a carotid artery dissection, or tear, in the right side of his neck.

The first surgery wrapped up Jan. 23. Two days later, Kirk had a second operation to create more space around his brain to accommodate swelling. Two small pieces of brain destroyed by the stroke were removed.

The section of Kirk's skull was reattached in a third operation Feb. 7. Within days, he was moved to the rehabilitation institute.

Physician Rebecca Gottesman, associate professor of neurology at Johns Hopkins Medicine in Baltimore, has treated hundreds of stroke patients. She and a colleague, given the outlines of Kirk's illness, agreed to speak generally about such strokes.

In cases like Kirk's, Gottesman said, she would expect an aggressive course of rehabilitation for three or four weeks or longer, likely involving occupational, physical and speech therapy and possibly therapy to help him swallow. Later, he may continue therapy while living at home or in an intermediate facility, she said.

"I tell my stroke patients, 'Where you are at in a year, or a year and a half, is where you are going to be,'" she said. "It doesn't mean it will take that long for everybody, but two or three months out, you are going to be making progress."

Gottesman said there should be no medical reason to restrict visitors, but there may be "public relations" considerations for stroke victims who are usually in the public eye. They may have slurred speech, for example, she said.

Some patients make a "tremendous" recovery, she said. "He could end up with mild weakness noticeable only to him, with normal speech, or he could be much more impaired or not be able to return to work."

Daniel Hanley, a professor of neurology and neurosurgery at Hopkins, found it "highly encouraging" that Kirk is already on a treadmill, but said it was not clear whether he was independently bearing his weight or walking with the assistance of safety belts.